program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils;

var
  i, s2, x1, y1, x2, y2, x3, y3 : integer;
  s : real;
  fin : textfile;
begin
  assignfile(fin, 'input.txt');
  reset (fin);

  read(fin, x1);
  readln(fin, y1);
  read(fin, x2);
  readln(fin, y2);
  read(fin, x3);
  readln(fin, y3);
  s2:=x1*y2-x1*y1+x2*y3-x3*y2+x3*y1-x1*y3;
  s:=s2/2;
  if (s<0) then
    s:=-s;
  writeln('The area of your treangle is:', s:0:1);

  closefile(fin);
  readln;
end.
